Ball or equivalent thrust bearing



July 5, 1949. R, c, MCLEQD 2,475,509

BALL OR EQUIVALENT THRUST BEARING Filed NOV. 15, 1945,

Patented July 5, 1949 BALL R EQUIVALENT THRUST BEARING Roderick Cristall McLeod, Cropston, England, assignor to Power Jets (Research & Development) Limited, London, England Application November 15, 1945, Serial No. 628,755 In Great Britain June 10, 1943 Section 1, Public Law .690, August 8, 1946 Patent expires June 10, 1963 14 Claims. 1

This invention relates to ball or like bearings. It has as its main object the provision of an arrangement and construction particularly applicable to bearings required to take axial thrust loads as well as journal loads. Whilst it is mainly concerned with ball bearings, it is conceivably also applicable to conical roller or like types of bearing, but following its main application it is proposed to describe the invention as applied to ball bearings only, the term being deemed to include such other similarly operating types.

It is well known that ball bearings can be made so that they are adapted to deal satisfactorily with axial thrust loads as well as journal loads, but in some applications it is not practicable for a single row bearing to be employed because, whilst speed and other factors control the size, it may be that the anticipated thrust load would be too high for the single row to deal with; the invention affords means whereby double or multiple rows of balls may be used as thrust bearings, the rows sharing the duty.

It has been previously proposed to construct a double ball thrust bearing in which the loads were intended to be balanced to some degree by virtue of being transmitted between the respective bearings and an abutment through a resilient medium.

According to this invention, a thrust bearing arrangement comprises two functionally independent ball bearings each arranged to transmit thrust, and substantially rigid means to which such bearings transmit their respective thrust loads, which means are adapted to balance these -loads against each other whilst reacting against the element to which the sum of the loads is to be transmitted. In stating that the bearings are functionally independent, it is intended to be implied that each is a complete bearing capable of functioning by itself irrespective of the other; indeed, as will be seen, in a typica1 example one bearing functions only as a thrust bearing whilst the other does duty as a journal bearing also. Further, according to the invention a thrust bearing arrangement may comprise two functionally independent ball bearings each arranged to transmit thrust, and means associated with each bearing to transmit its respective thrust load across the axial span occupied by the other bearing to a lever system to which the other bearing also transmits its thrust load, and the lever system is so arranged and adapted as to balance the two loads so applied and transmit their sum to the element which is to react the total thrust, e. g. to a stationary bearing housing forming part of a machine; this case of the invention is applied where thrust in both axial senses of direction is to be borne.

The invention includes arrangements which comprise two functionally independent ball bearings mounted adjacently upon a shaft (or the equivalent of a shaft) by their inner races, the outer races of each having or being associated with means for transmitting thrust load in either axial sense to rockable means arranged to balance the loads from each bearing against the load from the other bearing and to transmit the sum of such loads to an element which is to react the total thrust.

One of the bearings is preferably arranged and mounted so as to act as a journal bearing; and

preferably this bearing has its outer race supported through an axial spline arrangement allowing it axial freedom whilst restraining it radially and rotationally, whilst the outer race of the other bearing is restrained rotationally, conveniently by the means by which it transmits its thrust load in one axial sense.

The invention includes constructional features, including the mounting of the two bearings on a shaft, the bearings lying axially between two oppositely reacting sets of balancing means, the non-rotating elements of each bearing trans mitting loads in one axial sense directly to its neighbouring balancing means (Le. that to which it lies adjacent) and transmits loads in the other sense through the medium of intermediate means which axially span the alternative bearing.

If the bearings, as is preferred, have their outer races supported through partly-spherical surfaces within support rings, the latter are for purposes of description to be regarded as non-rotating elements of the bearings.

The balancing means preferably consist of annular series of rockable elements or levers each element being rockable about an axis which is positioned tangentially to an imaginary circle centred on the bearing axis. Inpreferred constructions therefore, a thrust bearing arrangement may comprise ball bearings mounted between two annular series of rocking elements spaced axially to accommodate the bearings, and the outer race of each bearing transmits thrust load in one sense to the radially outer parts of the balancing elements remote from such bearing through intermediate means which axially span the alternate bearing, whilst each outer race transmits thrust load inthe alternative axial sense directly to the radially inner parts of its proximate balancing elements, the rocking axes of the elements being disposed radially between their outer and inner parts.

In cases wherei-one (bearing is mounted to function as a journal bearing, the other bearing may have its associated thrust load transmitting means in the form of rods or equivalent separated elements which are axially slideably mounted in the non-rotating part (including supporting part) of the journal bearing.- H

The accompanying drawing illustrates one form of the invention, in which it is applied to :a double ball bearing adapted to actboth as ajournal and double acting thrust bearing. The drawing is a sectional arrangement, showing some surrounding parts so'far as these help the description. The particular application is to part of the shaft of a gas-turbine engine in which high speed is to.

be catered for so that large diameter bearings are unsuitable, and the diameter which is practicable from the speed point of View is too small to stand theaxial teats. theiiescribed case, atrial l-oad'in either directional sense can be met.

The shaft is seen at 1 a's' a hehow shaft with a step termed externally at: In, aga s-t'wl' i'ic h abuts the inner race 2A of a bearing assembly which has balls 23 and outer race QC. fitting on the shaft '1 behind the race ZA is as ac-ing collar 3-, and the inner race 'of the' second team g 7 race 40. For 10 v'ity it may as wel -to refer to the forward bear ng assembly 2A, 2131C, as tearing 2 and the rearward bearing assembly 4A, 4B, 40 as bearing 4. i

assembly which hes-inane 4B-an d outer Surrounding the snail; and bearin arrangemerits, is a bearing housing, which comprises in tact part of the strjietureo'f the machine s a. whole, and constitutes supporting means whidh is to react thrust from the shaft I This housin is shown asia iorwa-rd shell 5 and a rear is, these being held together by means not shown, and mutually locating by a sneuerw spigot 6A fitting into a suitable formation of shell 5.

Within the shell '5 an internally spin-led ring 1 is secured and this supports a bearing support ring 8 which is externally 's'plined to engage 1', and is axially drilled with .a circular series of holes which lie slidable' rods 8A. The holes interconnect channels .on :both flanks of 'the support 8, and inthese' channels lie rings 83,86 the interior edges of which bear on the ends'of the muscle. Instead of rings 83, $0, series of ar'c ua'te sections of rings may be employed, corresponding to the number of rods 8A. The interior of the-support ring 8 is formed with partly spherical contour, to correspond with the spherioally=formed outer surface of the track 20', in the manner wellknown for self-aligning bearings. The support ring 8 also has a circular rib, or preferably .a series of straight ribs, 813, formed-on one flank. The outer projecting edges of rings 83, 8C, are formed with rounded hoses or knife-edges (as also the rib 8D) to afford as nearly as possible line contact.

The shell 5, through an inset annular interme diate part 5A, supports a hardsteei annular ring 5B in a channel orrecess, andlbosely mounted also therein isa series of rocking plates 5G with bearing-ribs 513 which bear on the ring 5350 that each plate 50 can rock. The ring .83 bears the plates 50 with leverage, that is tosay to one side of rib 5D, and the rib 8D to the other side, so that .a plate 59 acts as a'rocke'r or lever on the pivot formed by 5D.

Thev foregoing describes in ffect'the arrange ment surrounding bearing 2. Bearing 4 is in some 8, is a frusto-conical hoop H], which is cut away .to pass the lugs 9A, and which extends outside n bearing 4, having at its rear edge a line-contact nose formation (at IUA) to bear on rocker plates l 1 against which the rib 9D also bears. The plates H are s pported rockably by the shell 6, just as in the corresponding above-described case.

The parts adjacent to the bearing are furnished with oil and air ducts, oil seals (e. g. labyrinths indicated at I2) scavenging arrangements, etc. as may be expedient. These form no part of the invention and so far as they need be understood, are shown in the drawing. The races 2A, 4A, are held by .a sleeve t4 forming partio-r the chatting and :scr'ew'ed tightly up by means not shown. Function is as follows. It will be clear that bearing 2 is operative quite normallyas a Journal bearing; bearing 4 is in this respect inoperative having no radial support capable of taking any load worth considering. Assumenow, a thrustin the shaft I, towards the left. This .is transmitted through two paths which finally unite in the r ib 5D, The load passes (in respect -:of bearing 2), through the following media. From l'4 through 4A8, 2A, 1213, 2C, 8, 813, 56 (where it is balanced against the remaining load), "5D, 53, 5A, to the shell 5 which finally reacts it. In respect of bear ing 4 the following is the chain; l4, 4A, 4B, 4C, s, on, so, BA, 78B, .50 (balancingLiD, 5B, 5A.

When the thrust in the shaft is from left to right, the corresponding chains of transmission apply: In respect of bearing 2, from'the. step 4A through 2A, 2B, 2C, -8, 10-, 10A, to ?l I and-thus to shell 6. In respect of bearing 4; from the step IA through 2A, 3-, 4A, 4B, 4C, 9, 9D, to ill and thus to shell 6, the plat-es I I again balancing the loads in the respective bearings.

It will be seen that, assuming appropriate th mensioning, the thrust load in each bearing is the same, or if it were required, the leverage in the plates 56 and I i could be so arranged :as to divide the sum of the loads in any required proportions between the bearings 2, 4.

If it were required to transmit very heavy thrust loads, the whole arrangement of the of bear ings could be duplicated again, through simiiar balancing devices, for further balanced subdivi sion of load.

I claim:

.1. A journal-thrust bearing assembly, being a bearing assembly in which the journal load is the major load and the thrust load the minor load, comprising twofunctionally independent bail bearings one of which carries the journal load and of which transmit thrust load, means to receive and react the total thrust transmitted by the said two bearings, mounting means for the said journal -thrust bearing permitting axial movement of a race thereof relative to said other bearing but restraining it radially and rotationally relative to said reacting means and means associated with said bearings to receive the thrust from each and associated with said reacting means to transmit the sumof such thrusts thereto whilst balancing one against the other.

2. A journal-thrust bearing assembly, being n bearing assembly in which the journal load is the major load and the thrust load the minor load,

for a shaft or equivalent comprising two functionally independent ball bearings disposed coaxially on the shaft or equivalent, one of which carries the journal load and both of which transmit thrust load, means to which the shaft is relatively rotatable to receive and react the total thrust transmitted by the said bearings, mounting means for the said journal-thrust bearing permitting axial movement of a race thereof relative to said other hearing but restraining it radially and rotationally relative to said reacting means and circularly disposed means coaxially associated with the said hearings to receive the thrust from each and associated with said reacting means to transmit the sum of such thrusts whilst balancing one against the other,

3. A. journal-thrust bearing assembly, being a bearing assembly in which the journal load is the major load and the thrust load the minor load, comprising a first ball bearing to carry the journal load and to transmit part of the thrust load, a second ball bearing to transmit the other part of the thrust load, an element mutually borne by said bearings, supporting means to which the rotation of the said element is relative and by which thrust from said element is to be reacted. mounting means for said first bearing permitting axial movement of a race thereof relative to said second bearing but restraining it radially and rotationally relative to said supporting means, rocker means pivotally associated with said supporting means to transmit thereto thrust loads, means for transmitting thrust from said race to said rocker means with leverage in one direction whereby the individual thrusts are balanced by said roclrer means and their sum is transmitted thereby to said supporting means.

4. A journal-thrust bearing assembly, being a bearing assembly in which the journal load is the major load and the thrust load the minor load, comprising a first ball bearing to carry the journal load and to transmit a part of the thrust load, a second ball bearing to transmit the other part of the thrust load arranged coaxially with the first bearing and axially adjacent thereto, an element mutually borne by said bearings, supporting means to which the rotation of said element is relative and by which thrust is to be reacted, mounting means for said first bearing permitting axial movement of a race thereof relative to said second bearing but restraining it radially and rotationally relative to said supporting means, rocker means pivotally associated with said supporting means to transmit thrust loads thereto, means for transmitting thrust from said race to said rocker means with leverage, and means spanning the axial dimension of said first bearing for transmitting thrust from said second bearing to said rocker means with opposite leverage whereby the individual thrusts are balanced by said rocker means and are thereby transmitted as a sum to said supporting means.

5. A double acting thrust bearing assembly comprising a first ball bearing adapted to transmit thrust, a second ball bearing adapted to transmit thrust arranged coaxially with the first bearing and axially adjacent thereto, an element mutually borne by said bearings, supporting means to which the rotation of said element is relative and by which thrust from the said element is to be reacted which means extends axially beyond the pair of bearings both ways outwardly, first and second rocker means pivotally associated with each such outward extension to transmit thrust loads thereto, means for transmitting thrust in onedirection from said first bearing with leverage to said first rocker means, means spanning the axial dimension of the said second bearing for transmitting thrust in the opposite direction from said first bearing with leverage to second rocker means, means spanning the :2 rial dimension of the first bearing for transmitting thrust-in one direction from said second bearing with opposite leverage to the first rocker means and means for transmitting thrust in the opposite direction from said second bearing with opposite leverage to the second rocker means whereby the individual thrusts in both directions are balanced by one or other rocker means and r therebytransmitted as a sum to said supporting means.

6. An assembly according to claim 5, in which one of said bearings being adapted to act journalwise is supported radially by said supporting means to transmit journal loads.

'7. A thrust bearing assembly comprising a first ball bearing adapted to transmit thrust and hav ing an outer support ring, a second ball bearing adapted. to transmit thrust and arranged coaxially with the first and axially adjacent thereto, an element mutually borne by said bearings, supporting structure to which rotation of said element is relative and by which thrust from said element is to be reacted, means to hold the first bearing radially and antirotationally in said structure whilst permitting relative axial freedom,

rocker means operatively disposed between said said second bearing against rotation, the rocker means and their operative connection with both bearings constituting a system to balance their thrusts whilst transmitting the sum thereof to said structure.

8. Assembly according to claim 7, in which said second bearing has a second outer support ring.

9. Assembly according to claim '7, in which said second bearing has a second outer support ring. and both support rings comprise so-called spherical mountings for the outer races of the respective first and second bearings.

10. Assembly according to claim 7, in which said second bearing has a second outer support ring, further comprising a hoop element extending axially from the first bearing support ring across the second support ring whilst engaging said second ring against rotation, and second rocker means disposed operatively between the second bearing and the supporting structure against which the second support ring and the hoop bear thrustwise with leverage to balance thereto from the two bearings and transmit their sum to said structure.

11. Assembly according to claim 7 in which said rocker means comprise rocker plates arranged in circular series concentric with the bearings and pivoted on axes tangentially in relation thereto.

12. A double thrust bearing assembly comprising a shaft, first and second ball bearings axially adjacently mounted thereon and each adapted to transmit thrust, first and second support rings supporting the outer races of said hearings in aemmoe I, I I a spherical man-hen, a supporting structure to react thrust from vsaidwshatt which is rotatable relative thereto such structure extending axially beyond the pair of bearings and enshrouding them, two circular series of rocker plates pivotally supported within and by said str-ucture outside said hearings each series to transmit thrust from the (hearings to the structure in one axial sense of direction, means whereby each outer ring transmits thrust :from its respective hearing to each series in one axial sense and to the other series in the opposite axial sense, such transmitting means being operatively related to the rocker means in sueha way as to balance the thrusts vfrom the two hearings in such rocker means whilst the sum of such thrusts is transmitted through the pivoted supports to said structure.

13. Assembly according :to claim 12, in which are further comprised radial splines between one 8 of saidsupport rings and said structure to support the respective bearingnradially whilst .permitting relative axial freedom.

14. Assembly according to claim 12, in which oneof said supporting rings in engaged with :the other against relative rotation, the said other ring Joeing engaged with said supporting structure against rotation. v

RODERICK GRISTALL MoLEOD.

REFERENCES crab Tn-eromming references are orreco'rd in the me of patent:

UNITED STATES PATENTS Number Name Date 11421982 Hall June 2'7, 1922 .1,"734;'223 Melott Nov. 5. 1929 

